Letters and abstract geometrical terms aside, there is something equally important and intriguing — perhaps even critical— to this 2-year-old with a Polaroid camera-like mind: Thomas the Tank Engine.

Or, as Jackson says in a quick, excited rhythm whenever someone mentions the little blue engine: “Thomas, Thomas, Thomas, Thomas.”

Jackson is just one of hundreds of thousands of children under the age of 6 enamored by Thomas, the central character in the “Thomas the Tank Engine & Friends” series seen on the award-winning “Shining Time Station” program. But he is one of few with the opportunity to see Thomas live in his own area.

That’s because Thomas — in one of only two appearances in North Carolina this year — will be at the N.C. Transportation Museum in Spencer for three days, Aug. 27-29. The life-size Thomas will be heading up the museum’s passenger train from 9 a.m. to 5 p.m. each day, providing Thomas fans with the chance to see their No. 1 engine and Sir Topham Hatt, another popular character from the show. There will also be special Thomas events that day, including face painting, coloring activities and games.

Tickets are $10 for adults and $5 for children ages 3-12 and can be purchased the day of the event.

The museum’s “A Day Out With Thomas” event is one of only 25 this year across the country. The special event is held primarily at railroad museums in the East. Organizers at Thomas‚ parent company, Britt Allcroft, expect more than 250,000 people to turn out for the events.

Thomas’ popularity with children and their parents can be traced to Allcroft, the writer and producer that brings the “cheeky, fussy little engine” to life.

“She’s the creative force behind Thomas,” said Beth Roche, a spokeswoman for the company in New York. “Britt Allcroft has helped change the look, style and content of quality children’s television around the world.”

Allcroft’s experience with the BBC and ITV UK networks in England helped fuel her creation of “Thomas the Tank Engine & Friends,” which was adapted from “The Railway Series” of books, written in 1945 by the Rev. W. Awdry.

The look of the Thomas films, which debuted in 1984 and are now a television phenomenon on four continents, is based on England of the 1940s and 50s. In Allcroft’s words, it is the reality of the environment created in the studio that is key to the magic of the Thomas films.

The engines, Thomas and his friends Percy, James and Gordon, and countless other characters are the heroes of the Thomas stories. To replicate a realistic environment on such a small scale, special lenses were developed to let the viewer virtually ride inside Thomas‚ cab. The result is an engine’s-eye-view for the viewer.

Thomas’ popularity on television has spread to other areas as well. Thomas merchandise — T-shirts, backpacks, coloring books, die-cast models, etc., are as popular as ever.

In the Gift Station at the N.C. Transportation Museum, anything “Thomas” is the most popular item.

“There’s always a new Thomas item coming out that the kids want,” said Kelly Alexander, who works for the N.C. Transportation Museum Foundation, the museum’s non-profit support group. “We can hardly keep the Thomas merchandise on our racks here at the Gift Station.”

Thomas is also on the Internet, where especially loyal fans can find out where he’‚s going to make his next appearance.

“We’ve had people calling from all over — Florida, New York, South Carolina, Kentucky, Virginia, Georgia, wanting to buy tickets,” said Alane Mills, a museum employee. “A lot of those people said they found out about Thomas coming to Spencer through the Internet.”

And then there’s the American military family who lives in Japan who timed their two-week visit back to the States around Thomas’ appearance at Spencer.

“It’s truly a phenomenon,” said Alexander. “People will come from all over to see Thomas. We’ve certainly learned that.”